Local Variable Gets Trashed by Temporary

Hi,
In the following code, the local variable 'b' gets overwritten when the line 'a += f2()'
executes.

Geoffrey

#pragma CALLEE-SAVES f2
long f2( void );

long f1( void )
{
unsigned char i, j;
long a, b;

j = 10;
do
{
i = 5;
a = 0;
do
a += f2();
while( --i );

if( j==10 )
b = a;
else
a -= b;
}
while( --j );

return a;
}